diff --git a/FAQ.md b/FAQ.md
index 729d732c..a3b58f4c 100644
--- a/FAQ.md
+++ b/FAQ.md
@@ -166,16 +166,16 @@ when connectivity changes from Wi-Fi/mobile, screen on/off and roaming/not roami
 **(21) Does doze mode affect NetGuard?**
 
 I am not sure, because the [doze mode documentation](http://developer.android.com/training/monitoring-device-state/doze-standby.html)
-is not clear if broadcast receivers will be disabled in doze mode.
-If broadcast receivers are being disabled, then the rules might not be reloaded at the correct time or not at all
-when connectivity changes from Wi-Fi to mobile or the other way around.
+is not clear if the [Android VPN service](http://developer.android.com/reference/android/net/VpnService.html) will be affected.
+
 To be sure you can disable battery optimizations for NetGuard manually like this:
 
 ```
 Android settings > Battery > three dot menu > Battery optimizations > Dropdown > All apps > NetGuard > Don't optimize > Done
 ```
 
-This cannot be done from the application, because NetGuard is not an application type allowed to do this.
+This cannot be done from the application,
+because according to Google NetGuard is [not an application type allowed to do this](http://developer.android.com/training/monitoring-device-state/doze-standby.html#whitelisting-cases).
 
 <a name="FAQ22"></a>
 **(22) Can I tether / use Wi-Fi calling while using NetGuard?**
diff --git a/app/src/main/java/eu/faircode/netguard/ActivityMain.java b/app/src/main/java/eu/faircode/netguard/ActivityMain.java
index 55fae6ef..8a577c92 100644
--- a/app/src/main/java/eu/faircode/netguard/ActivityMain.java
+++ b/app/src/main/java/eu/faircode/netguard/ActivityMain.java
@@ -32,7 +32,9 @@ import android.net.Uri;
 import android.net.VpnService;
 import android.os.AsyncTask;
 import android.os.Build;
+import android.os.PowerManager;
 import android.preference.PreferenceManager;
+import android.provider.Settings;
 import android.support.annotation.NonNull;
 import android.support.v4.content.LocalBroadcastManager;
 import android.support.v4.graphics.drawable.DrawableCompat;
@@ -55,6 +57,7 @@ import android.view.MenuInflater;
 import android.view.MenuItem;
 import android.view.View;
 import android.widget.Button;
+import android.widget.CheckBox;
 import android.widget.CompoundButton;
 import android.widget.ImageView;
 import android.widget.TextView;
@@ -75,6 +78,7 @@ public class ActivityMain extends AppCompatActivity implements SharedPreferences
     private MenuItem menuSearch = null;
     private AlertDialog dialogFirst = null;
     private AlertDialog dialogVpn = null;
+    private AlertDialog dialogDoze = null;
     private AlertDialog dialogLegend = null;
     private AlertDialog dialogAbout = null;
 
@@ -219,6 +223,8 @@ public class ActivityMain extends AppCompatActivity implements SharedPreferences
                     ServiceSinkhole.stop("switch off", ActivityMain.this);
             }
         });
+        if (enabled)
+            checkDoze();
 
         // Network is metered
         ivMetered.setOnLongClickListener(new View.OnLongClickListener() {
@@ -422,6 +428,10 @@ public class ActivityMain extends AppCompatActivity implements SharedPreferences
             dialogVpn.dismiss();
             dialogVpn = null;
         }
+        if (dialogDoze != null) {
+            dialogDoze.dismiss();
+            dialogDoze = null;
+        }
         if (dialogLegend != null) {
             dialogLegend.dismiss();
             dialogLegend = null;
@@ -448,8 +458,10 @@ public class ActivityMain extends AppCompatActivity implements SharedPreferences
             // Handle VPN approval
             SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
             prefs.edit().putBoolean("enabled", resultCode == RESULT_OK).apply();
-            if (resultCode == RESULT_OK)
+            if (resultCode == RESULT_OK) {
                 ServiceSinkhole.start("prepared", this);
+                checkDoze();
+            }
 
         } else if (requestCode == REQUEST_INVITE) {
             // Do nothing
@@ -622,6 +634,44 @@ public class ActivityMain extends AppCompatActivity implements SharedPreferences
         }
     }
 
+    private void checkDoze() {
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
+            PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE);
+            if (!pm.isIgnoringBatteryOptimizations(getPackageName())) {
+                final SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
+                if (!prefs.getBoolean("nodoze", false)) {
+                    LayoutInflater inflater = LayoutInflater.from(this);
+                    View view = inflater.inflate(R.layout.doze, null, false);
+                    final CheckBox cbDontAsk = (CheckBox) view.findViewById(R.id.cbDontAsk);
+                    dialogDoze = new AlertDialog.Builder(this)
+                            .setView(view)
+                            .setCancelable(true)
+                            .setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
+                                @Override
+                                public void onClick(DialogInterface dialog, int which) {
+                                    prefs.edit().putBoolean("nodoze", cbDontAsk.isChecked()).apply();
+                                    startActivity(new Intent(Settings.ACTION_IGNORE_BATTERY_OPTIMIZATION_SETTINGS));
+                                }
+                            })
+                            .setNegativeButton(android.R.string.no, new DialogInterface.OnClickListener() {
+                                @Override
+                                public void onClick(DialogInterface dialog, int which) {
+                                    prefs.edit().putBoolean("nodoze", cbDontAsk.isChecked()).apply();
+                                }
+                            })
+                            .setOnDismissListener(new DialogInterface.OnDismissListener() {
+                                @Override
+                                public void onDismiss(DialogInterface dialogInterface) {
+                                    dialogDoze = null;
+                                }
+                            })
+                            .create();
+                    dialogDoze.show();
+                }
+            }
+        }
+    }
+
     @Override
     public boolean onCreateOptionsMenu(Menu menu) {
         if (Build.VERSION.SDK_INT < MIN_SDK)
diff --git a/app/src/main/res/layout/doze.xml b/app/src/main/res/layout/doze.xml
new file mode 100644
index 00000000..9d032102
--- /dev/null
+++ b/app/src/main/res/layout/doze.xml
@@ -0,0 +1,56 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:orientation="vertical"
+    android:padding="16dp">
+
+    <LinearLayout
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:orientation="horizontal">
+
+        <ImageView
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_gravity="center_vertical"
+            android:src="@mipmap/ic_launcher" />
+
+        <TextView
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_gravity="center_vertical"
+            android:layout_marginLeft="8dp"
+            android:layout_marginStart="8dp"
+            android:text="@string/app_name"
+            android:textAppearance="@style/TextLarge"
+            android:textStyle="bold" />
+    </LinearLayout>
+
+    <ScrollView
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_marginTop="16dp"
+        android:orientation="vertical">
+
+        <LinearLayout
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:orientation="vertical">
+
+            <TextView
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:text="@string/msg_doze"
+                android:textAppearance="@style/TextMedium" />
+
+            <CheckBox
+                android:id="@+id/cbDontAsk"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:layout_marginTop="16dp"
+                android:text="@string/title_dontask"
+                android:textAppearance="@style/TextMedium" />
+        </LinearLayout>
+    </ScrollView>
+</LinearLayout>
\ No newline at end of file
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index b874e71a..bfcd819f 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -159,6 +159,8 @@ Your internet traffic is not being sent to a remote VPN server.</string>
     <string name="msg_mb">%1$7.3f&#9650; %2$7.3f&#9660; MB</string>
     <string name="msg_gb">%1$7.3f&#9650; %2$7.3f&#9660; GB</string>
     <string name="msg_count">%dx</string>
+    <string name="msg_doze">For consistent results, the Android battery optimizations should be disabled for NetGuard.
+\n\nIn the next dialog, select \"All apps\" at the top, tap on NetGuard in the list and select and confirm \"Don\'t optimize\".</string>
     <string name="msg_filter">Using filtering will cause Android to attribute data and power usage to NetGuard - Android assumes the data and power are being used by NetGuard, rather than the original applications</string>
     <string name="msg_log_disabled">Traffic logging is disabled, use the switch above to enable logging. Traffic logging might result in extra battery usage.</string>
     <string name="msg_clear_rules">This will reset the rules and conditions to their default values</string>
@@ -202,6 +204,7 @@ Your internet traffic is not being sent to a remote VPN server.</string>
     <string name="title_mediaserver">mediaserver</string>
     <string name="title_nobody">nobody</string>
     <string name="title_notify">Notify internet access attempts</string>
+    <string name="title_dontask">Don\'t ask again</string>
 
     <string name="title_log_whois">Whois %1$s</string>
     <string name="title_log_port">Port %1$d</string>